### Impact `XmlRenderer` pretty-prints XML by emitting depth-proportional indentation whitespace for **every** opening and closing tag. For a tree of depth n, the indentation alone sums to **O(n²)** bytes of output (and corresponding memory), reachable through `MarkdownToXmlConverter` — e.g. `str_repeat('> ', $depth) . "x\n"`, a single line of nested blockquotes — or through a direct `XmlRenderer::renderDocument()` call on an attacker-influenced AST. This affects applications that convert untr